SAN JOSE, Calif. (AP) - Marcus Smart had his pocket picked twice by Dominic Artis, missed four free throws and played like a jittery freshman instead of a heralded NBA prospect.

With its best player struggling all game, fifth-seeded Oklahoma State had little chance against the streaking Oregon Ducks.

Damyean Dotson scored 17 points and Artis had 13 points and four steals while shutting down Smart to help 12th-seeded Oregon beat the Cowboys 68-55 in the second round of the NCAA tournament Thursday.

"I definitely wish I could have done more for my team," Smart said. "I feel like I let my team down. I didn't contribute to my team the way that I usually do. And it hurt us a little bit."

Smart came into the game with the hype of a top NBA prospect but was held to 14 points on 5-for-13 shooting, a disappointing finish to a stellar season for the Cowboys (24-9). He turned the ball over five times, was 4 for 8 from the foul line and was unable to exploit his size advantage against Artis and Johnathan Loyd.

"Our quickness was important. I told D.A. and Johnny, there's no doubt he's more physical, much more powerful than you guys are, but I really believed they were quicker," Oregon coach Dana Altman said. "We had to get him away from the basket and try to use that quickness. And I thought D.A. and Johnny did a good job of that."

Smart also hurt his right hand in the second half and was scheduled to have tests to determine the extent of the injury. His future is also in question, and coach Travis Ford said he would talk with his star player soon about whether to enter the NBA draft.

Arsalan Kazemi added 11 points and 17 rebounds to give the Ducks (27-8) their first NCAA tournament win in six years.

Oregon, the Pac-12 tournament champion, advanced to play fourth-seeded Saint Louis (27-6) on Saturday for a spot in the Midwest Regional semifinals in Indianapolis next week. The Billikens beat New Mexico State 64-44.

The selection committee raised some eyebrows when Oregon was given a 12 seed despite tying for second place in the Pac-12 during the regular season, winning the conference tournament and going 21-4 with Artis in the lineup.

Ford said before the game that the Ducks looked nothing like a 12 seed and that was proven true in their tournament opener with the way they shut down Smart and hit their outside shots. Oregon's eight 3-pointers were their most since making nine in December against Houston Baptist.

"We ran into a very hot team," Ford said. "I've watched a lot of games on these guys and how they've played the last three games compared to how they were playing two or three weeks ago - this was a hot basketball team. I was impressed with Oregon, really impressed, and they came in here playing extremely well."

It was the Ducks' freshman backcourt that shined on this night, with Dotson hitting three 3-pointers in the first half to help build the lead and Artis playing well on both ends.

Artis frustrated Smart and also hit a 3-pointer that gave the Ducks a 54-38 lead midway through the second half in his best performance since missing nine games with a foot injury during the conference season.

"I made some shots that I usually hit, so that got me going," Artis said. "And then focusing on defense really helped the team."

His return late in the season helped pave the way to the Pac-12 tournament title for Oregon and has the Ducks playing their best at the most important time of year.

Smart and the Cowboys picked a bad time for a rough performance.

"It's frustrating," said Le'Bryan Nash, held to 10 points. "Winning 24 games, that's still a remarkable season, but being a fifth seed, it hurts a lot. I want to cry right now but I can't. I'm really hurt right now."

The Ducks had a decided crowd advantage on the West Coast, and even former UCLA star Bill Walton was decked out in a tie-dyed Oregon outfit.

There was plenty to cheer about in the first half for the Oregon fans after a sloppy start to the game that featured 10 turnovers in the opening 9 minutes.

Artis picked Smart twice to lead to fast-break baskets for the Ducks. Kazemi's slam on a putback gave Oregon a 19-12 lead as the Cowboys went nearly 6 minutes without scoring.

Carlos Emory's 3-pointer from the corner made it a double-digit game with just over a minute left and Kazemi beat the buzzer with a reverse off an airball by Dotson to give Oregon a 37-26 lead at halftime.

"I thought we came out a little, I don't know if it was nervousness, a little jittery, and the first half really set the tone," Ford said. "Hard to fight back."